We have used information from the National Center for Health Statistics (NCHS) and Bureau of the Census to create a comprehensive data base concerning mortality and population information at the county level. Data are available, 1950-1976, for cancer mortality, and 1965-76, for deaths from other causes. The data will be extended through 1978 when public use NCHS mortality tapes are received. Population data will be extended and corrected when the 1980 census data become available. Three-dimensional graphs employing these data are one example of the value of the data collection. A system for mapping counties in black-and-white is being developed, along with a system for analyzing projections of cancer mortality in the coming decades.